1. Field of the Invention
The present invention relates to a high-frequency device that includes a high-frequency circuit including an attenuator and that is formed as a single chip. The present invention also relates to a directional coupler that includes a high-frequency circuit including an attenuator and that is formed as a single chip.
2. Description of the Related Art
Known examples of a high-frequency device or high-frequency circuit related to transmission of high-frequency signals include, for example, the inventions disclosed in Patent Documents 1 to 6.
Patent Document 1 discloses a method of manufacturing a T-type attenuator including a conductor extending through a hole in a ferrite core.
Patent Document 2 discloses a signal transmission device that has high-band blocking and low-band transmission characteristics in which high-frequency components in a high-frequency band are absorbed.
Patent Document 3 discloses a high-frequency noise filter in which an LC circuit is formed as a result of a chip capacitor being connected to an outer magnetic plate of a multilayer inductor that is formed by stacking magnetic plates, having at least insulating surfaces and conductor portions formed on the surfaces, and by respectively connecting the conductor portions in series with one another.
Patent Document 4 discloses an attenuator including an inductor inserted in one line of a transmission path formed of a pair of lines and a pair of series circuits each formed of a resistor and a capacitor first ends of which are connected to the other line and second ends of which are respectively connected to the two ends of the inductor, where the inductor is formed by making a conductor line extend through a tube made of a magnetic body. The attenuator disclosed in Patent Document 4 is formed of discrete circuit devices including an inductor, resistors, and capacitors.
Patent Document 5 discloses a ferrite sintered body, a chip inductor, and an LC composite component.
Patent document 6 discloses a general directional coupler.    Patent Document 1: Japanese Examined Patent Application Publication No. 3-015363    Patent Document 2: Japanese Unexamined Patent Application Publication No. 8-078218    Patent Document 3: Japanese Unexamined Patent Application Publication No. 62-189712    Patent Document 4: Japanese Unexamined Patent Application Publication No. 63-098206    Patent Document 5: Japanese Unexamined Patent Application Publication No. 1-110708    Patent Document 6: Japanese Unexamined Patent Application Publication No. 2011-055457